Pressurized fluid distribution systems are used in a wide variety of industries, such as oil pipelines that distribute oil removed from the ground to supply tankers; commercial irrigation systems employed by large farms to supply water from the well to the crop fields; lawn watering systems used by homeowners to maintain lush, green lawns and healthy, decorative plantings and the like. In all of such systems, remote valves are employed to control the flow rate and/or timing of the supply of fluid to segments or "zones" of the system such as, for example, to different parts of a crop field in plant irrigation. The remote valves or zone valves are also used in conjunction with nozzles or "heads" that directly supply the water to the plants to control the supply of water thereto. The use of zone valves and heads in combination is employed in lawn irrigation systems which may include a plurality of zones. Each zone receives water from a number of heads having a common zone valve.
In most instances, the zone valves supplying fluid to the different segments or zones of a fluid distribution system are operated by electronic or pneumatic signals received from a central location. The signals actuate a motor or solenoid associated with the zone valve to control the flow and/or timing of fluid therethrough to the zone. Such valves not only are more complicated in their design and operation, but also require the use of electrical wires or pneumatic control piping which run from the central signal generating location to the valve. As a result, the additional equipment, installation time and associated fixed, installation and operating costs reduce the utility of these systems. Such is particularly the situation in areas of the world where utilities such as electricity or pressurized gas are scarce, or the distribution systems are less well developed.
Another problem associated with zone valves is providing adequate water pressure from the water source to the zone valve. The greater the number of zones that is to be irrigated, the greater the number of outlets or valves in the pipe line which supplies the water. The more outlets added to the pipe line, the greater the chances are that there may be an inadequate pressure drop at many of the valves along the pipe line. Thus, a number of zones may not receive an adequate supply of water.
Unlike the centrally controlled zone valves used in fluid distribution systems, the zone valves associated with the final outlets or nozzles are not controllable as to rate and/or timing but rather operate merely to raise the nozzle to a height intended to ensure that water supplied to the nozzle is distributed by the nozzle to a predetermined area of the field to be irrigated. Alternatively, some zone valves are designed to interrupt the flow of water to an outlet which has no associated nozzle as disclosed in U.S. Pat. No. 5,372,306.
U.S. Pat. No. 4,632,361 to Callison discloses a fluid control valve which purports to perform a preestablished sequence of flow rates and timing schedules in response to pressure pulses in a controlled fluid. As disclosed, pressurized fluid causes an actuation mechanism, a plate or cylinder, to rotate along a path defined by a cam and cam follower arrangement such that fluid ports defined in the plate or cylinder of predetermined size and placement come into and out of fluid communication with the inlet and outlet ports of the valve, thus enabling the control of the fluid flow rate and/or timing. The '361 patent also discloses that a plurality of control surfaces may be substituted to select a large number of fluid flow schedules and flow rates. A disadvantage of the Callison valve is the many parts which increases the cost of the valve, and compromises the valve's reliability.
Although there is a fluid flow control valve that purports to control fluid flow and timing, there is still a need in the art of fluid flow distribution an inexpensive, reliable, programmable, fluid flow control valve capable of controlling flow rate and/or timing of fluid passing through the valve. There is also a need for a programmable, fluid flow control valve capable of supplying fluid to a number of zones without the problem of an inadequate pressure drop.
An objective of the present invention is to provide a programmable fluid flow control valve capable of controlling flow rate and/or timing of fluid passing through the valve.
Another objective of the present invention is to provide a programmable fluid flow control valve capable of supplying fluid to a number of segments or zones.
A further object of the present invention is to eliminate or reduce the problem of inadequate pressure drop in a valve when providing fluid to a number segments or zones.
Other objects and advantages of the present invention will become apparent to those skilled in the art upon practicing the invention.